Japan

Hiroshima Heavyweight launches on Expressway Line 5

On September 18, 2018, a Robbins slurry machine, measuring 13.7 m in diameter, made its first cut into hard rock

On September 18, 2018, a Robbins slurry machine, measuring 13.7 m in diameter, made its first cut into hard rock for the Hiroshima Expressway Line 5 project in Japan. The launch at an urban jobsite was made possible by Onsite First Time Assembly (OFTA) of the TBM. The contractor, a joint venture of Obayashi-Taisei-Kosei, had a strict timeline of eight months to adhere to when it came to machine assembly. “This deadline was very important. After assembling the TBM, I think OFTA was appropriate for this project,” said Mr. Ryota Akai, Deputy Project Manager for the Obayashi JV.

Due to the project location there were also restrictions on delivering the TBM—in order to meet controlled transportation limits within the city, the TBM had to be divided into small transportable weights and sizes, then assembled in a small jobsite, 30 m wide and 60 m long. The 2400 metric ton machine will bore 1.4 km of the 1.8 km long tunnel that, once completed, will significantly improve traffic conditions in Hiroshima. The new Expressway Line 5 tunnel will directly connect Hiroshima’s urban area with a major national highway network and is expected to improve access to Hiroshima Airport. Tunnel completion is planned for 2020.

The massive machine is the country’s first foreign-made large diameter Slurry TBM to excavate hard rock in Japan. The machine is expected to encounter granite with rock strengths up to 130 MPa UCS. Those involved in the project are excited to see what effect this will have on how Slurry TBMs are used in the future.

The design of the Slurry machine is robust in anticipation of potentially abrasive rock conditions and water pressures up to 13 bars. In preparation for the conditions, the machine was designed for 20-bar water pressure. The robust cutterhead was fitted with 20-inch and 17-inch diameter pressure compensating cutters, which utilize a patented design to effectively operate under high pressure. The joint venture intends to change the disc cutters an estimated 10 times during the bore as part of the machine’s maintenance.

x

Related articles:

Issue 06/2020

Hiroshima Heavyweight: Slurry Tunneling in Japan’s Hard Rock

Project Background Japan’s Hiroshima Expressway Line 5 is designed to improve access between Hiroshima Station and the national Sanyo Expressway via Hiroshima Expressway Line 1. Specifically, the new...

more
Issue 03/2021

Diameter Change – USA’s Largest Hard Rock TBM Undergoes Planned In-Tunnel Conversion

The drainage relief tunnel in Dallas, Texas, USA is an important project, as the tunnel will provide 100-year flood protection for east and southeast areas of the city--locations affected in recent...

more
Issue 05/2011

Innovations and Limitations of Two Long-Standing Soft Ground TBM Designs

EPB and Slurry TBMs, first developed in the 1960s and refined in the decades following, were designed around very different philosophies. Though both prototypes originated in Japan, EPBs were founded...

more

Job offers - Technical engineers with focus areas in Slurry TBM & Hard rock TBM (Gripper, Telescope TBM)

22.05.2015 Erkelenz, Germany CREG TBM Germany GmbH Technical engineers with focus areas in Slurry TBM & Hard rock TBM (Gripper, Telescope TBM) more information (Download PDF)...

more
Issue 06/2014 Turkey

Kargi Hydroelectric Project: TBM conquers difficult Ground

Multiple fault zones, variable face conditions and squeezing ground requiring extensive bypass tunneling: These were just a few of the challenges overcome in order to successfully complete Turkey’s...

more